The present invention relates in general to a defrosting tool and in particular to a tool for maintaining certain interior surfaces of a cryostat in frost-free condition. The interior surfaces referred to are the interface surfaces normally contacted by a removable cold head of the cryostat.
In order for the cold head to achieve the intended purpose of cooling the cryostat, it is important to maintain low thermal contact resistance at the interface surfaces. When the cold head is removed, e.g. for servicing and/or repair, moisture from air in contact with the cold, exposed interface surfaces precipitates on these surfaces and forms a layer of frost which increases the thermal contact resistance. The removal of this frost layer presents a problem because the interface surfaces are located deep inside the cryostat cavity and are therefore not easily accessible. Measures taken heretofore to cope with this problem have produced inadequate results. For example, hot air has been blown into the cavity in order to melt and evaporate the frost layer. Such a procedure can require as many as six hours before the frost covered surfaces are completely cleared. Other measures taken to date have been similarly unsuccessful.
Accordingly, it is a principal object of the present invention to provide apparatus for substantially reducing the amount of time required for removing the frost formed on the exposed interface surfaces of a cryostat.
It is another object of this invention to provide a new and improved tool for removing frost that forms on the exposed interface surfaces of a cryostat in minimum time and to maintain these surfaces in frost free condition pending the return of the cold head to the cryostat.